A vehicle-mounted air conditioner in an electric vehicle, a fuel-cell electric vehicle and the like, on which no engine is mounted, has a compressor in which an electric motor is built, as a power source that compresses and circulates a refrigerant. Because it is necessary that this electric motor rotate at a desired rpm according to an instruction from a main control apparatus of the air conditioner, it is necessary to separately provide a control apparatus. This control apparatus is composed of electric circuits and electronic circuits. Specifically, this control apparatus is provided with switching elements (power transistor elements), such as IGBTs (insulated gate bipolar transistors) and FETs (field effect transistors) for constituting what is called an inverter circuit (a switching circuit), including electronic elements, such as central processing units and memories. From space-saving requirements, an electric compressor in which this control apparatus, along with a compression mechanism and an electric motor, is built in one housing is under study. In the following, this electric compressor may sometimes be referred to as an integrated electric compressor.
Compared to a stationary electric compressor, large vibrations and impacts are applied to an integrated electric compressor mounted on a vehicle. With respect to this problem, Patent Document 1 makes the following proposal.
That is, in an integrated electric compressor, it is necessary to connect an inverter circuit and an external electronic control unit (ECU) by use of a multicore communication cable and similarly it is necessary to connect a battery and the inverter circuit by use of a power cable. In order to facilitate the assembling, replacement and repair of this integrated electric compressor, it is most suitable to combine the power cable, communication cable and inverter circuit by use of connectors. However, as described above, in an integrated electric compressor, vibrations and impacts acting on connections obtained by connectors are exceedingly large and, therefore, there is a possibility that the electrical contact properties of terminals of the connectors worsen.
Therefore, Patent Document 1 describes that a motor-side power connector and a motor-side communication connector are composed of a connection terminal, which is substantially vertically provided in a standing manner, and a resin body part, which is formed integrally with a resin frame part so that a cable-side power connector and a cable-side communication connector can be substantially vertically inserted and extracted. Patent Document 1 describes that according to this arrangement, the terminals of the motor-side connectors and the terminals of the cable-side connectors provide facing surfaces in substantially horizontal directions so as to be slidable substantially vertically and, therefore, the vibration resistance is significantly improved compared to other terminal connection conditions.
Patent Document 1: Japanese Patent No. 3802477
Incidentally, if an inverter circuit is separated into a power board that converts a direct current supplied from a high-voltage power source into an alternating current and applies the alternating current to an electric motor and a control circuit board that controls the application of the alternating current to the electric motor, it is possible to reduce the area of the inverter circuit in a planar direction. Therefore, this contributes to the downsizing of an integrated electric compressor. In this integrated electric compressor, it is effective to perform the fixing of the power board to the control circuit board by using pin-like terminals provided on the power board side for the downsizing of the integrated electric compressor. The pin-like terminals include at least two kinds of terminals. One is a terminal for signal transmission between the power board and the control circuit board, and the other is a terminal for the grounding of the power board and the control circuit board.
According to examinations by the present inventors, which will be later described in detail, it became apparent that the pin-like terminal may be broken if vibrations are applied to the power board and the control circuit board.
In an integrated electric compressor in which the fixing of a power board to a control circuit board is performed by using pin-like terminals provided on the power board side, the present invention has as its object to prevent the breakage of the pin-like terminals due to vibrations.